Electric-arc lamp



no Model.)

B. R. KNOWLES. ELECTRIC ABC LAMP.

No. 516,826. Patented Mar. 20', 1894.

the feed gear.

STATES PATENT OFFICE.

EDWARD EK owLEs, OF MIDDLETOWN, OONNEOTlCUT, Ass ICNOE TO THE SOHUYLERELECTRIC COMPANY, OF CONNECTICUT.

ELECTRIC-ARC LAM P.

SPECIFICATION forming part of Letters Patent No. 516,826, dated March20, 1894.

I Application filed July 17,1893. Serial No. 480,688. (No model To allwhom it may concern.-

Be it known that I, EDWARD R. KNOWLES, a itizen of the United States,residing at Middletown, in the county of Middlesex and'State ofConnecticut, have invented certain new and useful Improvements inElectric -Arc lamps, of which the following is a specifica-Theseimprovements relate especially to details in the focusing arc lampused in search lights, though applicable of course to other styles oflamp. They have reference to the manner of attaching the shield, theelectrical connection between the sliding negative carbon holder and itssupport, the feeding gear, the tension device for the feed-pawlarmature, and the make and break contacts in the shunt circuit.

In the drawings: Figure 1 is a side elevation of a focusing arc lampembodying my improvements. Fig. 2 is a rear view of the shield on theline 22. Fig. 3 is a detail of Figs. 4: and 5 are details of the tensiondevice.

Rising from the base A is an inclined post B, on which is rigidlyfastened a sleeve 0 having on one side an arm 0 having a T- shaped head0'. The shield D rests against the face of this head 0, and is providedwith two fiat spring fingers d which slip down over the back of the head0' and hold the shield firmly in place, but permit it to be easily andquickly removed by sliding it upward off the head.

The holder E for the negative carbon is attached to a carrier 6 whichslides on a bar F rigidly fastened to the block f mounted to slide onthe post B, and actuated by the feed screw G. Electrically connectedwith one of the lamp contacts H, by means of a jointed arm I, is theseries or are striking electromagnet K, carried on the block f. Thearmature lever 70 of this magnet is connected with the sliding carriere, whereby the magnet is enabled to separate the carbons, by depressingthe carrier as indicated by dotted lines in Fig. 1. The electricalconnection between the carrier and the magnet coil is by means of a linkis running from the-terminal of the coil to an insulated collar on thebar F, and a flexible copper conductor L between said collar and thecarrier 6. This conductor is of one or more separate strands'or. layers,thin enough, to give it great flexibility, so that it can accommodateitself to the relative movements of the block and carrier.

In order to take up wear, and prevent backlash between the pinion M andgear M of the feeding mechanism, the pinion is journaled eccentricallyin a cylindrical bushing N mounted in a cylindrical hole in the side ofthe lamp base. After turning the bushing to adjust the pinion toward .oraway from the gear-wheel, the bushing can be fastened by the screws 11.On the same shaft as the pinion is the ratchet wheel O,which is drivenby the pawl P carried on the lever Q which is vibrated by the shuntelectro-magnet of the feed mechanism, in the usual manner. The lever hasa tension spring R, which is fastened to the end of the screw R on whichis a circular nut R for adjusting the tension of the spring. A springarm S is fastened to the lamp-base, and its free end has a curved face 5to fit the periphery of the nut R The nut 7 5 and the curved face on thearm are milled or roughened, so that the arm serves to lock the nutagainst accidental movement, as by the jarringof the mechanism, whileyet permitting it to be readily turned by the attendant when necessary.

The make and break of the shunt circuit are effected by the lev Q, hichhasan arm q playing between adjustable stops t t on the movable contactT, which slides stifliy in a holder U. The opposite Contact T is alsoadjustable by means of a screw 1?. By adj usting the stops, the feed canbe made coarse or fine at will.

Having thus describedmy invention,what I claim is- 1. In a focusing arclamp, the combination with a T-shaped head, of a shield adapted to restagainst the face of the head, and having spring-fingers to slide downover the back of 5 the head, substantially as shown and described. v

2. In a focusing arc lamp, the combination with the pinion M and gear 1of the feed mechanism, of the cylindrical bushing N in which said pinionis eccentrically journaled, ing arm playing between said stops, substan-[0 said bushing being mounted in a cylindrical tially as shown anddescribed.

hole in the lamp base, and provided with In testimony whereof I hereuntoset my means for looking it when adjusted, substanhand in the presenceof two witnesses.

5 tially as shown and described.

3. In a focusing arc lamp, the combination EDWARD KNOWLES with the shuntcircuit, of a pair of contact Witnesses: w points, one of which slidesin a holder and is D. J. GLAZIER, provided with adjustable stops, and avibrat- Jos. T. ELLIOTT.

